Studio Tech Tip - Patch Bays, Part 1
By Dennis Kambury

At first, everything seems simple enough. With your guitar, mic, and keyboard plugged into your 12-channel mixer; a digital reverb hanging off of the aux bus; and your recorder being fed off the direct outputs, everything is wired and ready to go. Then you add a digital delay and a compressor, and a couple other pieces of gear, and you suddenly find yourself constantly unplugging and replugging to get the connections you want. When you reach this level, it's time to think about adding a patch bay to your setup. This week, we'll look at patch bays and their connections, and cover some terminology. Next week, we'll take a look at how to get the most out of your bay.

The concept
At its most basic, the patch bay's purpose is to bring all your input and output connections to one easy-to-access location. Your normal connections are maintained, and any temporary changes are easily made with a short patch cord. There are a wide variety of patch bays available, from handy, budget-priced unbalanced 24-point units to expensive, hand-soldered 96-point military-spec bays. For the sake of brevity, we'll focus on one of the best solutions for the project studio - the 48-point balanced TRS bay that uses jacks on both the front and rear. A good, low-cost example of this type of bay is the ACE APB-48S.

What is normal?
Let's say that your normal setup includes the output of your synth output plugging into the first channel of your mixer. When you incorporate a patch bay, the output from your synth plugs into the first jacks in the back of the bay, and the bottom jack is then connected to the first channel of the mixer. The signal is automatically routed from the top jack to the bottom jack, or in patch bay lingo, normalled.

This is virtually the same electrically as plugging directly from your synth into the mixer. Occasionally, you may want to use a different synth on channel one. Instead of dragging cable to the back of your mixer, unplugging the original cable, and plugging in the new one, all you need to do now is plug into the input of the patch bay:

By inserting a plug into the input of the bay, it breaks the normal connection made by the rear jacks, and feeds the mixer with the output of your new synth.

Note that the output of the original synth is still accessible on the front of the bay, and can be re-routed to another mixer input if desired. Because only the bottom half of the patch bay is actually switching in the above example, this particular configuration is known as half-normalled. This is the standard configuration of most patch bays out of the box. However, there is another configuration that is equally useful: isolated or de-normalled. This allows you to bring the I/O of occasionally used processors such as EQ or compression to the patch bay without connecting them to themselves.

By rotating the card inside the patch bay, you reverse the front and rear connections, changing the configuration so that the permanent rear input breaks the normalled connection, preventing a feedback loop.

Next week, we'll delve into ideas for setting up your patch system, and how to take advantage of all these new connections.

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